A large amount of nitrogen oxides (NOx) harmful to a human body is produced in the combustion process of automobile engines and fossil fuel use facilities such as a power generation facility, an industrial boiler and an incineration facility, and the discharge of these nitrogen oxides (NOx) has a significant influence on air pollution, such as acid rain, a reduced ozone layer and generation of photochemical smog.
As a process for removing them, selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) which spray a reducing agent (NH3, etc.) to a catalyst, a process using an electron beam, a pulse corona discharge process, and the like have been studied and developed. As nitrogen oxide reduction technology is developed, emissions of nitrogen oxides have been slightly decreased over the past decade, however, about 30 million tons of nitrogen oxides are still emitted annually only in the United States, and in the case of using the selective catalytic reduction (SCR) which is most widely used for removing the nitrogen oxides, an astronomical amount of about 24 billion dollars is required.
In addition, a BioDeNox process for treating nitrogen oxides (NOx) using microorganisms has been newly developed and becomes popular. The BioDeNox process is the most recent technology, and allows the nitrogen oxides (NOx) to be treated even at room temperature using microorganisms, unlike other processes, thereby significantly reducing energy consumption. The core of this technology is excellent selective binding capacity and binding rate of divalent ferric-ethylenediaminetetraacetic acid to nitrogen monoxide (NO), and in the course of reaction, the divalent ferric-ethylenediaminetetraacetic acid is oxidized to trivalent ferric-ethylenediaminetetraacetic acid which is an inactive form by oxygen contained in exhaust gas, and thus, a regeneration process should be necessarily included. Since the BioDeNox method uses microorganisms which may reduce trivalent iron ion in this regeneration process, the reduction rate is significantly slow, and a lot of energy and cost are consumed in treating separated nitrogen oxides (NOx).
Korean Patent Registration No. 1522857 discloses a composite type selective reduction catalyst. This patent discloses a catalyst having improved purification ability at low temperature, by using a composite SCR catalyst having a bilayer structure, being coated on a carrier (substrate), in which a V2O5/TiO2 layer is formed in an upper layer, and a metal-contained zeolite layer is formed in a lower layer, however, since vanadium and titanium which are expensive rare earth precious metals are used, it costs a lot of money for preparation.
Korean Patent Registration No. 1189238 discloses a nitrogen oxide adsorption-reduction catalyst. This patent discloses a catalyst including a carrier including Li and Al; a nitrogen oxide-adsorption element of an alkali metal, an alkali earth metal or a rare-earth element; and one or more precious metals selected from the group consisting of Pt, Pd, Ru, Ag, Au and Rh, thereby having excellent adsorption ability even before and after deterioration and before and after sulfation, however, since the catalyst uses a large amount of rare-earth precious metals, it costs a lot of money for nitrogen oxides adsorption.
Thus, the present inventors devoted extensive effort for solving the problems, and as a result, developed an electrolysis apparatus for collecting a nitrogen compound using Fe-EDTA, and as a result of performing a nitrogen oxide collecting test using the electrolysis apparatus, confirmed that the nitrogen compound in exhaust gas may be efficiently collected, with the use of expensive rare-earth elements being minimized, thereby completing the present invention.
The above information described in the Background Art is only for improving understanding of the background of the present invention, and thus, may not include information forming the prior art which is already known to a person with ordinary skill in the art to which the present invention pertains.